Documenting surface magmatic activity at Mount Etna using ATSR remote sensing

Analysis of thermally generated night-time volcanic radiances recorded with a 1-km pixel size at 1.6 and 11 mum during 1991-1993 and 1996-1999 for Mount Etna shows that lava flows extending beyond the summit craters can be distinguished from vent activity. The two phenomena plot in different regions of feature space when the mean volcanic radiance (per anomalous pixel) at 11 mum is plotted against the mean volcanic radiance at 1.6 mum. The distinct feature space characteristics of lava flow fields are apparent within 1-2 days of the onset of each effusive event. Such a plot also enables lava flow fields being fed by open channels to be distinguished from tube-fed flow fields. Rank order analysis of the total 1.6-mum volcanic radiance series shows that vent activity and lava flows belong to different populations, and offers further scope for remotely identifying changes in eruptive state.